Browsing by Author "Shrestha, Sajana"

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    Antifungal activities of some medicinal plant extracts and Trichoderma spp. against stemphylium vesicarium of allium sativum
    (Department of Botany, 2010) Shrestha, Sajana
    The extracts of eight aromatic plants viz. Cuscuta reflexa, Syzygium aromaticum, Allium cepa, Cinnamomum zeylanicum, Solanum xanthocarpum, Phyllanthus emblica, Cinnamomum camphora and Equisetum diffusum were assessed in-vitro for antifungal activity against Stemphylium vesicarium; the causal organism of leaf blight of garlic. Pathogenicity test was confirmed by inoculating the pathogen into healthy garlic plant. The assessment for fungitoxicity was carried out by poisoned food technique using five different concentrations (20%, 40%, 60%, 80% & 100%) against the test fungus in terms of percentage of mycelial growth inhibition. Among the test plants, the extracts of Cuscuta reflexa, Syzygium aromaticum and Allium cepa were able to inhibit the mycelial growth completely. Trichoderma spp. was tested to determine its effect on mycelia growth of S. vesicarium on PDA medium. The mycelia growth was totally inhibited by Trichoderma spp. showing its fungitoxic properties.
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    Responses of Some Crops to Air Pollution by Using Air Pollution Tolerance Index
    (Faculty of Botany, 2020) Shrestha, Sajana
    Responses of plants toward the air pollution were assessed by air pollution tolerance index (APTI). APTI is calculated from the values of different biochemical parameters of plant leaves such as relative water content, total chlorophyll content, ascorbic acid content, and leaf extract pH by using standard methods. Plants with a high index value were tolerant of air pollutants and vice-versa. Based on their indices, different plant groups were categorized into sensitive, intermediate, and tolerant. This study was aimed to identify the most tolerant and sensitive crop plants. The present study was carried out to evaluate the air pollution tolerance index (APTI) of eight economically important winter crop plants. Plants were cultivated in polluted site 1 (Thamel), polluted site 2 (Banasthali), and less-polluted site (Phutung) in Kathmandu based on vehicular movement. The result of the study showed higher APTI values in polluted site 1 than in less-polluted sites and polluted site 2. Among the studied species, Brassica juncea (10.69±1.07), Brassica campestris (10.45±0.88), Triticum aestivum (9.74±0.77) and Hordeum vulgare (9.64±1.00) respectively were recorded high APTI values indicating resistance to pollution and Trigonella foenum-graecum (7.52±2.08) with the lowest APTI value indicating sensitive to pollution. The impact of the air pollutants on crop productivity was also measured from the selected crop plants. The result revealed that plant growth was found to be reduced in polluted sites. And Triticum aestivum (64.48±31.53 kg ha -1 ) was a high productivity crop plant while low was Trigonella foenum-graecum (2.09±0.68 kg ha -1 ). The response of crop plants was varied in species, studied sites, and level of pollution. Hence, this study helps to identify the tolerant crop plant which can act as a good absorbent of air pollutants.